Astyanax brachypterygium

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Astyanax brachypterygium
Astyanax brachypterygium illustration.png
Illustration of a female specimen
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Characiformes
Family: Characidae
Genus: Astyanax
Species:
A. brachypterygium
Binomial name
Astyanax brachypterygium
Bertaco & Malabarba, 2001
Synonyms [2]

Astyanax brachypterygyrium (lapsus) Bertaco & Malabarba, 2001

Contents

Astyanax brachypterygium is a small species of freshwater fish endemic to a collection of high-elevation streams in Brazil. It was named in 2001 alongside congener Astyanax cremnobates, to which it bears a strong resemblance; physical details (and a separate native range) help to differentiate between the two. Its scales are a greenish-brown on the back and silver on the belly, with reddish fins and a dark humeral spot. One of its defining features is a notably short anal-fin base, which has 13 to 15 rays.

It usually inhabits shallow waters with a good current, but little else of its ecology has been researched, including diet, behavior, and mating practices. Several species are known to live in peaceful sympatry with it. The IUCN has given A. brachypterygium a near threatened classification due to a decline in habitat quality, largely thanks to anthropogenic survival pressures. [1]

Taxonomy

Astyanax brachypterygium was first described in 2001 by Brazilian ichthyologists Vinicius A. Bertaco and Luiz R. Malabarba. [3] Its only known synonym is Astyanax brachypterygyrium, with an extra "yr", which was provided in error as part of the original treatment. [2] [4] It is known to be affiliated with species in the Astyanax scabripinnis species complex, [5] which makes it a part of the subgenus Astyanax. [6] There are three total subgenera in the genus Astyanax; the other two, aside from Astyanax itself, are Poecilurichthys and Zygogaster. [7]

Some preliminary research suggests that A. brachypterygium be considered a junior synonym of congener Astyanax cremnobates, [6] which was named in the same 2001 paper. [8]

Etymology

The specific name originates in Greek. "Brachys" means short, and "pterygion" means fin; this is in reference to the short anal-fin base. The genus name Astyanax is from the Iliad, wherein Astyanax was the son of Trojan prince Hector. [9]

In Brazil, A. brachypterygium is sometimes referred to as lambari-de-cabeceira; [1] worldwide, it has no accepted common name. [10]

Description

Astyanax brachypterygium reaches a maximum length of 6.4 cm (2.5 in) standard length, SL. [4] There are 13–15 anal-fin rays, which is a much lower number than almost every other member of the genus; counts therein range from 20 to 45. There are 11 or 12 pectoral-fin rays, occasionally 10 or 13. There are 6 or 7 pelvic-fin rays, and 8–10 rays in both lobes of the caudal fin. There are 35–37 scales in the lateral line. [5] The eye takes up roughly one-quarter of the head's length. [11]

Astyanax brachypterygium has a brown-green back and a silver belly. The fins are mostly tinted reddish, with the exception of the pectorals, which are clear, and the adipose, which is slightly yellowish. There is also a patch of yellow on the middle caudal-fin rays. [12] There is a main humeral spot that demonstrates vertical elongation, and a secondary humeral spot that connects to the dark lateral stripe. This secondary spot may be diffuse, and is not always obvious upon examination. [5] On occasion, the area just behind the primary humeral spot may be pale. [13]

Astyanax brachypterygium bears enough of a resemblance to congener Astyanax cremnobates that the two have been considered for synonymy by some researchers. [6] Several morphometric differences exist, however. A. cremnobates has a larger eye diameter, more anal-fin rays, and a thinner caudal peduncle in comparison to A. brachypterygium; further, the native ranges are different. [14] A. cremnobates is also ~3 cm (~1 in) longer than A. brachypterygium. [15]

Another species, Astyanax pampa , bears further similarities to A. brachypterygium, but can be told apart by its much longer anal-fin base in comparison. [16]

Sexual dimorphism

Male specimens of A. brachypterygium have bony hooks on the rays of the anal and pelvic fins. Males also have longer pelvic fins than females. The anal fin is smoothly concave in female specimens, while it is straight in males. Females are also generally longer than males, by slightly less than a centimeter. [5]

Distribution and ecology

Astyanax brachypterygium is endemic to headwater streams of the upper Uruguay and Jacuí River basins in Brazil. [4] [12] This distribution is considered relatively restricted, which is not uncommon for species in the A. scabripinnis complex. [17] [18] Amongst sites with specific occurrence records, it is relatively more common in the Lajeadinho stream, and slightly less so in the Marco river. [19]

Astyanax brachypterygium was originally collected at an elevation of 1050 m, but it can be collected as far as 1100 to 1200 m above sea level. [20] In these locales, biodiversity is low, which makes for fewer sympatric species; however, those collected alongside it include Pareiorhaphis hystrix , Rhamdia quelen , and Jenynsia eirmostigma . [19] It generally prefers shallow streams with a healthy flow. [1] Dietary needs are unknown.

The Lajeadinho stream floods on a regular basis, and is surrounded by floodplains as a result. [21] Unsurprisingly, the locale is subject to significant rainfall, though not on a constant basis. [22] The Marco river is a waterway with a strong current and rocky substrate, as well as a sparse riparian zone. [23]

Conservation status

Astyanax brachypterygium has been evaluated by the IUCN as a near threatened species. Recently, there has been a notable decline in the quality of its habitat, attributable to several anthropogenic factors; these include destruction of the riparian zones, introduction of invasive species, and the construction of hydroelectric dams. [1]

Related Research Articles

<i>Astyanax</i> (fish) Genus of fishes

Astyanax is a genus of freshwater fish in the family Characidae of the order Characiformes. Some of these fish, like many of their relatives, are kept as aquarium pets and known collectively as tetras. With around 150 described species and new ones being described yearly, this genus is among the largest of the entire order; Hyphessobrycon also has more than 145 species and which one is larger at any one time depends on whether more species have been recently described in one or the other. The blind and colorless cave tetra of Mexico is a famous member of the genus, but its taxonomic position is disputed: Some recognize it as part of the Mexican tetra and this is supported by phylogenetic evidence, but others recognize the cave form as a separate species, A. jordani.

<i>Ectrepopterus</i> Species of fish

Ectrepopterus uruguayensis is a small species of characin originally recorded only from streams in Uruguay, with occasional sightings in Brazil and Argentina. It is the only known member of the genus Ectrepopterus, which was formerly a subgenus of Megalamphodus. Given its restricted range, it is considered a rare fish, and is of note for conservation researchers interested in preserving the biodiversity of the region.

Astyanax microschemos is a species of characid fish from Brazil. It belongs to the A. scabripinnis species complex and differs from other species outside it by having a lower number of branched anal fin rays and its shallow body depth being about 26.9-29.7 vs more than 35% of its standard length (SL). Compared to species of its own complex, it can be distinguished by the combination of its shallow body depth, and smaller interorbital width. The species name comes from the Greek mikroschemos, meaning "low stature", which refers to the shallow body depth of the animal.

<i>Deuterodon pelecus</i> Species of fish

Deuterodon pelecus is a species of characid fish from Brazil. It can be distinguished from other species by: its body depth ; its short and pointed snout smaller than the orbital diameter; and a reduced number of branched anal fin rays. D. pelecus also differs from members of its genus by its characteristic color pattern. It possesses a single humeral spot that is constricted to the region above the lateral line; at the same time it shows a conspicuous midlateral body stripe from opercle to the caudal fin base, an autapomorphy of this precise species. Other Deuterodon species have a humeral spot that is vertically or horizontally elongate and have the midlateral stripe becoming faint near that humeral spot. The species name is derived from the Greek pelekus, meaning "axe", referring to the pigmentation shape resulting from the adjoinment of the humeral spot with the midlateral stripe.

<i>Carlastyanax</i> Genus of fishes

Carlastyanax aurocaudatus is a small species of freshwater fish in the family Characidae native to the Río Cauca in Colombia. It is the only member of the monotypic genus Carlastyanax, which was named in 1972 specifically for the species by Jacques Géry. Upon description, it was named Astyanax aurocaudatus by Carl H. Eigenmann. There has been debate concerning whether or not the genus should be recognized, but C. aurocaudatus is currently considered a valid species.

<i>Astyanax argentatus</i> Species of fish

Astyanax argentatus is a small freshwater fish native to northern Central America and southern North America. Given its native range, it is also known as the Texan tetra. Little has been published regarding the feeding habits or behavior of A. argentatus, but it is known to have the northernmost distribution of any member of the genus Astyanax.

Bryconops munduruku is a small freshwater fish of the family Iguanodectidae that lives in the rivers of South America. Its adipose fin is black, with a clear base, and it has two humeral spots, which is a feature it shares with few congeners. Its fins are a variety of yellow, red, black, and clear, and mature males have hooks on select fin-rays.

<i>Astyanax abramis</i> Species of fish

Astyanax abramis is a small freshwater fish from the inland rivers of South America. It is plentiful in almost the entire continent, with a habitat including the La Plata, upper Amazon, and Meta River basins. The body shape is subrhomboidal and laterally compressed, and the scales are largely silver, with a blue or green tint on the dorsal side.

<i>Astyanax angustifrons</i> Species of fish

Astyanax angustifrons, sometimes referred to as the Campeche tetra, is a small freshwater fish from the rivers of Central and South America. It has a healthy distribution across southern Mexico and northern Guatemala, and is relatively common within its native range. Details regarding its diet and behavior are sparse, but it lives in areas with plentiful riparian vegetation, and most other members of the genus are omnivorous. Its habitat includes places affected by pollution and human activity; nonetheless, it is not endangered.

<i>Astyanax aramburui</i> Species of fish

Astyanax aramburui is a small freshwater fish from the rivers of South America, restricted to a relatively small region within the Paraná and Uruguay river basins of Argentina. It was named after the scientist who established a professional presence for ichthyology in the country, Raúl Arámburu. Considered a near-threatened species by the IUCN, its range includes creeks in a sub-basin affected by various forms of pollution.

<i>Astyanax argyrimarginatus</i> Species of fish

Astyanax argyrimarginatus is a small species of freshwater fish native to various river basins in Brazil. Originally thought to be restricted to the Tocantins-Araguaia river system, a study in 2012 expanded its range to include the Rio Xingu, as well. Specific biotope preferences are unknown, but it is mostly collected from clearwater streams in fairly good health. Its relative abundance and presence in some protected locales means that it is not endangered.

<i>Astyanax asuncionensis</i> Species of fish

Astyanax asuncionensis is a small species of freshwater fish described in 1972 from Asunción, the capital of Paraguay in South America. Its specific epithet is in reference to this. Currently, its range is known to encompass areas of not just Paraguay but also Argentina and Brazil. It is an adaptable, omnivorous species that easily lives in sympatry with various congeners.

<i>Astyanax bacalarensis</i> Species of fish

Astyanax bacalarensis, sometimes referred to as the Bacalar tetra, is a small species of freshwater fish found in Central and South America. Its scientific and common names both refer to its type locality, Lake Bacalar in Mexico, and it further inhabits freshwater environments like cenotes, streams, and wetlands. Its widespread nature, paired with an omnivorous diet, make it a hardy species.

<i>Astyanax bagual</i> Species of fish

Astyanax bagual is a small species of freshwater fish known only from the Taquari-Antas river basin in southern Brazil. It is unusual in the genus Astyanax because mature male specimens display bony hooks on the rays of all fins; in opposition, most others have them on the anal, pelvic, or pectoral fins - sometimes on more than one of these, but very rarely on all fins. It can further be told apart from various congeners by way of dentition and some aspects of coloration, including the presence of two humeral spots instead of one.

<i>Astyanax biotae</i> Species of fish

Astyanax biotae is a small species of freshwater fish native to various localities in Brazil. It primarily eats invertebrates, like copepods and aquatic fly larvae, and its diet also includes seeds, fruits, and filamentous algae. Its scales are largely silver, with a touch of yellow-brown on the back and a hint of blue on the sides. Like many species of Astyanax, it has a humeral spot, which is a blotch of pigmentation in the area above or around the pectoral fin.

<i>Astyanax bourgeti</i> Species of fish

Astyanax bourgeti is a small species of freshwater fish native to the upper Amazon river in Brazil. Originally described in 1908, it is not a particularly well-studied member of the genus Astyanax, but there is enough information available to establish a native range, an appearance, and potential relationships to congeners; for example, A. bourgeti is a known member of the subgenus Poecilurichthys, and has been considered such for most of its existence. Biotope preferences, sympatry, diet, and behavior are all unknown.

<i>Astyanax brevirhinus</i> Species of fish

Astyanax brevirhinus is a small species of freshwater fish known only from a river basin in northeastern Brazil. It is somewhat understudied and lacks a conservation status, but it is present in a region that is the subject of an ecological restoration project - the Jequitinhonha River. Specifics of diet and behavior are unknown, though shoaling activity has been observed in laboratory conditions.

Astyanax apiaka is a small freshwater fish endemic to the Apiacá river in Mato Grosso, Brazil. Its discovery is recent, as of 2023, which results in little published research of its natural behaviors or preferred biotopes. However, descriptions of its appearance and general environment have been solidified, as well as some baseline information regarding its diet. It lacks a conservation status from the IUCN.

<i>Astyanax clavitaeniatus</i> Species of fish

Astyanax clavitaeniatus is a small species of freshwater fish native to various rivers in the Amazon basin. It is characterized by a club-shaped lateral stripe, which is where it gets its scientific name; "clava" means "club", and "taenia" means "stripe". It is a deep-bodied fish with a silvery base color, which is not uncommon for members of Astyanax. Its markings - including a humeral spot and two vertical brown bars - indicate that it is a part of a species complex centered around congener Astyanax bimaculatus.

Astyanax anai is a small freshwater fish native to Central America. It has a restricted range, inhabiting a handful of Atlantic drainages in Costa Rica and Panama, and is known from locales only up to 100 meters elevation. As an endangered species, A. anai is a point of interest for conservation biologists studying the region. It can be found living sympatrically with other species of Astyanax, but is less common than its relatives.

References

  1. 1 2 3 4 5 Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio) (2022). "Astyanax brachypterygium". IUCN Red List of Threatened Species (in Portuguese). 2022: e.T186802A1818599. doi: 10.2305/IUCN.UK.2022-1.RLTS.T186802A1818599.pt . Retrieved 6 June 2023.
  2. 1 2 Bailly, Nicolas (2017). "Astyanax brachypterygium Bertaco & Malabarba, 2001". WoRMS. World Register of Marine Species . Retrieved 6 June 2023.
  3. ↑ "Astyanax brachypterygium Bertaco & Malabarba, 2001". www.zoobank.org. International Commission on Zoological Nomenclature. Retrieved 7 June 2023.
  4. 1 2 3 Froese, Rainer; Pauly, Daniel (eds.) (2023). "Astyanax brachypterygium" in FishBase . June 2023 version.
  5. 1 2 3 4 Bertaco, Vinicius A.; Malabarba, Luiz R. (October 2001). "Description of two new species of Astyanax (Teleostei: Characidae) from headwater streams of Southern Brazil, with comments on the A. scabripinnis species complex". Ichthyological Exploration of Freshwaters. 12 (3): 221–234.
  6. 1 2 3 Oliveira, Carlos Alexandre Miranda (2017). Revisão taxonômica do complexo de espécies Astyanax scabripinnis sensu Bertaco & Lucena (2006) (Ostariophysi: Characiformes: Characidae) (PhD thesis). Universidade Estadual de Maringá. hdl:1834/10128 . Retrieved 6 June 2023.
  7. ↑ Rossini, Bruno César; Oliveira, Carlos Alexandre Miranda; Melo, Filipe Augusto Gonçalves de; Bertaco, Vinicius de Araújo; Astarloa, Juan M. Díaz de; Rosso, Juan J.; Foresti, Fausto; Oliveira, Claudio (19 December 2016). "Highlighting Astyanax Species Diversity through DNA Barcoding". PLOS ONE. 11 (12): e0167203. Bibcode:2016PLoSO..1167203R. doi: 10.1371/journal.pone.0167203 . PMC   5167228 . PMID   27992537.
  8. ↑ "SUMMARY: Bertaco, Vinicius A. & Luiz R. Malabarba. 2001. Description of two new species of Astyanax (Teleostei: Characidae) from headwater streams of Southern Brazil, with comments on the "A. scabripinnis species complex"". www.zoobank.org. International Commission on Zoological Nomenclature. Retrieved 7 June 2023.
  9. ↑ Scharpf, Christopher; Lazara, Kenneth J. (19 June 2024). "Family CHARACIDAE: Subfamily STETHAPRIONINAE Eigenmann 1907 (American Tetras)". The ETYFish Project. Retrieved 10 July 2024.
  10. ↑ "Astyanax brachypterygium Bertaco & Malabarba 2001". Encyclopedia of Life . National Museum of Natural History.
  11. ↑ Haluch, Carolina Ferreira; Abilhoa, Vinícius (September 2005). "Astyanax totae, a new characid species (Teleostei: Characidae) from the upper rio Iguaçu basin, southeastern Brazil". Neotropical Ichthyology. 3 (3): 383–388. doi: 10.1590/S1679-62252005000300005 .
  12. 1 2 Malabarba, Luiz R.; Fiaho, Clarice B.; Anza, Juan A.; Ferrer, Juliano; da Silva, Giovanni N. M. (January 2009). "Peixes". In Boldrini, Ilsi (ed.). Biodiversidade dos campos do Planalto de Araucárias. Brasília: MMA. p. 144. Retrieved 7 June 2023.
  13. ↑ "Astyanax joaovitori". Global Biodiversity Information Facility . Retrieved 2023-06-07.
  14. ↑ Lucena, Carlos A. S. de; Castro, Jonas Blanco; Bertaco, Vinicius A. (September 2013). "Three new species of Astyanax from drainages of southern Brazil (Characiformes: Characidae)". Neotropical Ichthyology. 11 (3): 537–552. doi: 10.1590/S1679-62252013000300007 .
  15. ↑ Froese, Rainer; Pauly, Daniel (eds.) (2023). "Astyanax cremnobates" in FishBase . June 2023 version.
  16. ↑ Casciotta, J R; Almiron, A E; Azpelicueta, M (2005). "Astyanax pampa (Characiformes, Characidae), a". Revue suisse de Zoologie. 112: 401–408. doi: 10.5962/bhl.part.80305 . S2CID   83145428.
  17. ↑ de Lucena, Carlos Alberto S.; Zaluski, Amanda Bungi; de Lucena, Zilda Margarete Seixas (18 September 2017). "Astyanax taurorum a new species from dos Touros River, Pelotas River drainage, an upland southern Brazilian river (Characiformes: Characidae)". Zoologia. 34: 1–8. doi: 10.3897/zoologia.34.e20174 .
  18. ↑ Tagliacollo, Victor A.; Britzke, Ricardo; Silva, Gabriel S. C.; Benine, Ricardo C. (31 December 2011). "Astyanax pirapuan Tagliacollo, Britzke, Silva & Benine, 2011, new species". treatment.plazi.org. Plazi TreatmentBank. doi:10.5281/zenodo.5680236 . Retrieved 7 June 2023.
  19. 1 2 Winckler-Sosinski, L.T.; Schwarzbold, A.; Schulz, U.H. (2009). "Fish assemblage structure in altitude rivers under the effect of exotic species introduction, northeast of Rio Grande do Sul, Brazil" (PDF). Acta Limnologica Brasiliensia. 21 (4). Retrieved 7 June 2023.
  20. ↑ Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Species related to Astyanax brachypterygium". Catalog of Fishes . California Academy of Sciences . Retrieved 7 June 2023.
  21. ↑ Volcan, Matheus Vieira; Lanés, Luis Esteban Krause; Gonçalves, Ândrio Cardozo (1 May 2010). "Pisces, Cyprinodontiformes, Rivulidae, Austrolebias periodicus (Costa, 1999): Distribution extension in state of Rio Grande do Sul, southern Brazil". Check List. 6 (2): 234. doi: 10.15560/6.2.234 .
  22. ↑ Córrego Lajeadinho, Mato Grosso do Sul, Brazil, Mindat.org , retrieved 6 June 2023
  23. ↑ Dias, Tatiana S; Fialho, Clarice B (June 2011). "Comparative dietary analysis of Eurycheilichthys pantherinus and Pareiorhaphis hystrix: two Loricariidae species (Ostariophysi, Siluriformes) from Campos Sulinos biome, southern Brazil". Iheringia. Série Zoologia. 101 (1–2): 49–55. doi: 10.1590/S0073-47212011000100006 .
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